Measuring high in ports

作者：Arno Kijzerwaard

在货物运输的intermodal containers keeps growing in volume, ship sizes show a steady increase as well. As a consequence, ports around the world have to invest in larger container cranes in order to handle these ships.

These container cranes are increasing in operating speed as well as in their level of automation. Trolley traveling speeds up to 240 or even 300 metres per minute are no exception anymore. On a track of 100 m, these trolleys easily travel more than 10,000 kilometres per year.

One of the key elements to crane maintenance at these high speeds is the wear, caused by the wheel-rail contact of the trolley. Effective prevention of this aggressive form of wear is realised by an accurate alignment of the trolley wheels. On a container crane with a girder height of more than 50 m, however, this alignment procedure puts extreme demands on measurement instruments.

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保持正轨

Though the alignment measurement of a set of steel wheels on steel rails seems a straight forward activity that could be performed by almost anyone in possession of a theodolite, this proves far less simple when located 50 m high on a moving steel structure in the wind. Not to forget one had to travel half the world to even get there.

在集装箱起重机上的手推车车轮的准确对齐是一个专业和利基市场，以至于市场区域仅由世界各地的港口形成。Langeveld Cranes在这项技术方面拥有将近十年的发展，使其达到了全新的水平。到现在为止，他们估计的成功项目数量约为全球300个。

Langeveld has been using a Leica TS30 total station and recently added a Leica Nova TS60 total station to its equipment basket. The TS60 is used in combination with a Leica CS35 tablet computer and Langeveld’s own specially developed wheel alignment software.

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在极端工作

Tolerances for wheel alignment date back to the 1970s. Classic crane design standards all specify maximum allowable wheel angles of 0.4 mm/m. This is, however, not quite the same as describing good running behaviour. By approaching the alignment from the side of good running behaviour, a whole new accuracy level was achieved in the practical end result.

This new accuracy level, though beneficial, puts higher demands on the accuracy and reproducibility of the measurements. The total stations have to measure up to the demands over and over again. The work of Langeveld’s trolley wheel alignment is so much more accurate than ever specified in the history of crane standards. This in itself is one thing, but it’s also significant that this result is always achieved on a height of more than 50 m from quay level on a moving crane in the wind.

Climate is another critical aspect to consider. The temperature working range of measurement equipment is usually one line in the data sheet. Hardly a difficult specification to meet when measuring close to Langeveld’s home base in the Netherlands. This becomes a less theoretical value, however, when winter projects in Scandinavia are asked for, followed by tropical destinations around the equator.

After dozens of these projects, the TS30 total station has remained stable. Of course, the instrument is acclimatised prior to each working day. Still, extreme variations of ambient temperature are no longer theoretical values in this line of work.

“In every thinkable climate, all over the world, our Leica Geosystems total stations have travelled to ports on almost all continents, and passed through the hands of custom officials in many countries in Africa, the Middle East, Asia and South America,” said Casper Langeveld, owner, Langeveld Project Management. “No matter the form of transport or the environmental conditions, these total stations continue to work and provide us with the measurements we need. We are able to trust the results and ensure quality deliverables for our clients.”

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New trends, new needs

起重机自动化的最新发展意外导致了全新的挑战。经典的起重机驾驶员通常位于他的负载上方。立即注意到并做出反应。这可能是服务工程师的无线电呼吁之间的任何东西，或者在最坏的情况下，是一个完整的起重机停止。

起重机自动化增加和遥控器的最新趋势有效地从起重机中移走了驾驶员。这意味着手推车行为中没有直接见证人的震惊或噪音。因此，手推车必须比以往任何时候都更加光滑，因为声音或震动的任何偏差都会在更长的时间内保持不变。

Meeting the international demands and work volume, the TS60 was an easy choice for the firm as a natural successor to the TS30. With ATRplus, the TS60 total station's ability to remain locked on the target is maximised, ignoring other distractions in the field, which can be plentiful in a port.

As Langeveld’s own software runs on the TS60, along with the possibility of also using Leica Captivate 3D field software, this is a crucial feature for the firm. This enables the internal communication to the total stations for a cohesive work environment.

Langeveld说：“我们相信Leica Geosystems为我们的业务提供的整体强大解决方案。”“我们为起重机市场组成了一个强大的团队。”